Construction and Assembly of the first Barrel Slice for the

Electromagnetic Calorimeter of the PANDA Experiment

K.T. Brinkmann1, M.Moritz1 ,A. Ryazantsev2, P. Wieczorek5, B. Wohlfahrt1 and H.-G. Zaunick1 for the PANDA-Collaboration

12nd Physics Institute, Justus-Liebig-University Giessen, Germany 2IHEP Protvino, Protvino, Russia

3GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany

Corresponding authors:

Markus Moritz, markus.moritz@exp2.physik.uni-giessen.de

Hans-Georg Zaunick, hans-georg.zaunick@exp2.physik.uni-giessen.de

Heinrich-Buff-Ring 16, 35392 Gießen, Germany

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The PANDA electromagnetic calorimeter (EMC) and the recent prototypes

Prototypes:

• Small sections of one barrel slice

The readout concept of the EMC

Assembly of single Detectors

• Placement of 40 crystals in a type 7 alveole block

2 LAAPDs (7x14 mm2) read out simultaneously by one APFEL ASIC

• Two channels with different gains for each LAAPD

• Dynamic range of 10000 (1 MeV to 12 GeV)

• Programmable amplification of 16/32

• High rate capability (up to 500 kHz)

• Low power consumption: 55 mW/ch

Conclusions

and Outlook

Energy resolution (3x3 submatrix)

Feature extraction Line shapes

• Energy = maximum - pedestal

• Assembly of first slice segment of the PANDA Barrel EMC nearly finished

• Mass production established for crystal detectors and modular detector blocks

• Calibration and energy resolution extensively studied with close-to-final prototype PROTO120

• A submatrix of depolished (uniformized light yield) crystals was tested and improvement for energy resolution demonstrated

• The next steps are: installation of insulation, cooling and test measurements

Expected Performance of the Calorimeter (TDR requirements and earlier prototype setups)

APD response

Results obtained with final PROTO120

prototype

In agreement with TDR requirement

• Roughening of one side

...surface by controlled

...polishing with fixed grain size

Light collection and Non-UniFormity (NUF)

Impact on energy resolution

The planned PANDA detector @ FAIR

Target EMC barrel part of the EMC

PROTO60

PROTO120

Barrel EMC:

• 15552 PbWO4 crystals (length: 20 cm ~ 22 X0)

• 13 crystal types (different degree of tapering)

• Type 1: most tapered, type 13: least tapered

• Operation temperature: -25 °C

one slice

SADC:

• 50/125 MHz

• No additional

timing branch

Glueing station

Linear energy response

APD pre-assembly treatment

• Both APDs show a linear

correlated response in the

region of the dynamic range

Reduction of NUF improves the energy resolution

. at higher energies

trace

recorded

by SADC

Single crystal noise level: 0.9 – 1.0 MeV

Single crystal threshold: 2.8 – 3.0 MeV

Single crystal

light collection

. is homogenized

Cluster sum

Optical fibers

Preamplifiers Alveole inserts

Crystals with APDs

Carbon alveoles

Thermal shield

Support feet

Support beam

Drivers

FPGA:

• Online pulse data

processing

Assembly of Modules

• Rear view (off-beam)

including flat cables of

embedded PT100

sensors

• Front view (beam facing)

• Precise mounting of

APDs in glueing

gauges with defined

glueing force

• Assembled

detector wrapped

in reflective foil

and equipped with

termination

capsule

• APDs irradiated with 60Co

gammas and screened for

matching characteristics

Assembly of Supermodules

Assembly of first Barrel Slice

• A Supermodule consisting of .

. three Modules